In recent years, the demand has been substantially expanded for batteries as power sources for portable electronic devices such as cellular phones and portable personal computers. In the batteries for use in such applications, electrolytes (electrolytic solutions) such as organic solvents have been conventionally used as media for moving ions.
However, the batteries configured above are at risk of causing the electrolytic solutions to leak out. In addition, the organic solvents or the like for use in the electrolytic solutions are flammable materials. For this reason, there has been a need to further increase the safety of the batteries.
Therefore, as one of countermeasures for increasing the safety of the batteries, it has been proposed that solid electrolytes are used as the electrolytes, in place of electrolytic solutions. Furthermore, the development of all-solid batteries which use solid electrolytes as the electrolytes and have other constituent elements also composed of solids has been advanced.
For example, Japanese Patent Application Laid-Open No. 2007-294429 (hereinafter, referred to as Patent Document 1) proposes a method for producing a lithium-ion conducting solid electrolyte by firing a compact while applying pressure. Specifically, Patent Document 1 discloses that the firing was carried out while applying a pressure up to 180 MPa on the compact.
For example, Japanese Patent Application Laid-Open No. 2010-10110 (hereinafter, referred to as Patent Document 2) proposes a method for producing a solid electrolyte by firing a compact while the pressure acting from a setter to the compact is set to 500 kg/m2 or less.
For example, Japanese Patent Application Laid-Open No. 2009-224318 (hereinafter, referred to as Patent Document 3) proposes a method for producing an all-solid battery by heating for firing a mixture of an electrode active material and a solid electrolyte while pressure is applied thereto. Specifically, Patent Document 3 discloses carrying out a heat treatment with a pressure of 500 kg/cm2 applied, thereby baking electrodes on both sides of the solid electrolyte base.
Patent Document 1: Japanese Patent Application Laid-Open No. 2007-294429
Patent Document 2: Japanese Patent Application Laid-Open No. 2010-10110
Patent Document 3: Japanese Patent Application Laid-Open No. 2009-224318